One of my best friends, Chris Delaney, died in Gore Canyon - August 2000.  I wasn't there but he was with close friends at the time.  It is such a tragedy and VERY hard to deal with a loss like this.  I guarantee that he will be with you and many others everytime you hit the water from this point forward.  Not to mention in just about everything you do.

His family will probably be shaken the most since they might not agree with how it happened, but it helped me greatly to realize that this is how he would have wanted to go (In Chris's case).  I would rather have dealt with the Kayaking incident than a car crash or something else with no significance.  Their accident's are similar in that it happened on a run that was litteraly done 100 times before - which almost makes it harder to bear.

Life is short, regardless.  My outlook is that it is better to live a life doing what you love and risk dying doing it, than to worry about what might of happened and die NOT doing it.  

My best to you and all of Jon's friends and family.  I am sure he will be missed greatly.